Clinical lung transplantation from uncontrolled non–heart-beating donors revisited

Uncontrolled donation after circulatory death: European practices and recommendations for the development and optimization of an effective programme

The shortage of organs remains one of the biggest challenges in transplantation. To address this, we are increasingly turning to donation after circulatory death (DCD) donors and now in some countries to uncontrolled DCD donors. We consolidate the knowledge on uncontrolled DCD in Europe and provide recommendations and guidance for the development and optimization of effective uncontrolled DCD programmes.

Expanding the lung donor pool: advancements and emerging pathways

PURPOSE OF REVIEW

The number of patients listed for lung transplantation largely exceeds the number of available transplantable organs because of a shortage of organ donors and a low utilization rate of lungs from those donors who are available. In recent years, novel strategies have been developed to increase the donor lung pool: improved donor management, the use of lungs from donations after cardiac death (DCD), the use of lobar lung living-donors (LLLD) and the use of ex-vivo lung perfusion (EVLP) to assess and repair injured donor lungs.

RECENT FINDINGS

An adapted donor management strategy could expand the donor pool up to 20%. DCD lung transplant is an increasing part of the donor pool expansion. Outcomes after controlled DCD seem to be similar to donation after brain death. LLLD transplantation has excellent results for small and critically ill patients. EVLP treatment allows for a significant increase in the rate of suitable lungs and represents an optimal platform for lung reconditioning and specific lung therapies.

SUMMARY

A significant increase in the number of available lungs for transplantation is expected in the future because of the wider use of lungs from controlled or uncontrolled DCD and LLLD lungs, and with organ-specific EVLP treatment strategies.

Ex vivo lung perfusion

Lung transplantation is an established life-saving therapy for patients with end-stage lung disease. Unfortunately, greater success in lung transplantation is hindered by a shortage of lung donors and the relatively poor early-, mid-, and long-term outcomes associated with severe primary graft dysfunction. Ex vivo lung perfusion has emerged as a modern preservation technique that allows for a more accurate lung assessment and improvement in lung quality. This review outlines the: (i) rationale behind the method; (ii) techniques and protocols; (iii) Toronto ex vivo lung perfusion method; (iv) devices available; and (v) clinical experience worldwide. We also highlight the potential of ex vivo lung perfusion in leading a new era of lung preservation.

Controlled non-heart beating donor lung transplantation: initial experience in Spain

Although the number of lung transplants in Spain is increasing annually, more organs are required to ease waiting lists. Controlled non-heart beating donors (NHBD) (Maastricht III) are a reality at international level, and contribute significantly to increasing donor numbers. In this study, we present our NHBD protocol and the initial experience in Spain using lung grafts from this type of donor. Three bilateral lung transplants were performed between January 2012 and December 2014. Preservation was by ex-vivo lung perfusion in 2 cases and by traditional cold ischemia in the other. None of the patients developed grade 3 primary graft dysfunction, no in-hospital mortality was recorded and 1-year survival was 100%. These initial results, and international experience, should help to develop similar protocols to encourage the use of controlled non-heart beating donors.

Protocols for uncontrolled donation after circulatory death: a systematic review of international guidelines, practices and transplant outcomes

INTRODUCTION

A chronic shortage of organs remains the main factor limiting organ transplantation. Many countries have explored the option of uncontrolled donation after circulatory death (uDCD) in order to expand the donor pool. Little is known regarding the variability of practices and outcomes between existing protocols. This systematic review addresses this knowledge gap informing policy makers, researchers, and clinicians for future protocol implementation.

METHODS

We searched MEDLINE, EMBASE, and Google Scholar electronic databases from 2005 to March 2015 as well as the reference lists of selected studies, abstracts, unpublished reports, personal libraries, professional organization reports, and government agency statements on uDCD. We contacted leading authors and organizations to request their protocols and guidelines. Two reviewers extracted main variables. In studies reporting transplant outcomes, we added type, quantity, quality of organs procured, and complications reported. Internal validity and the quality of the studies reporting outcomes were assessed, as were the methodological rigour and transparency in which a guideline was developed. The review was included in the international prospective register of systematic reviews (Prospero, CRD42014015258).

RESULTS

Six guidelines and 18 outcome studies were analysed. The six guidelines are based on limited evidence and major differences exist between them at each step of the uDCD process. The outcome studies report good results for kidney, liver, and lung transplantation with high discard rates for livers.

CONCLUSIONS

Despite procedural, medical, economic, legal, and ethical challenges, the uDCD strategy is a viable option for increasing the organ donation pool. Variations in practice and heterogeneity of outcomes preclude a meta-analysis and prevented the linking of outcomes to specific uDCD protocols. Further standardization of protocols and outcomes is required, as is further research into the role of extracorporeal resuscitation and other novel therapies for treatment of some refractory cardiac arrest. It is essential to ensure the maintenance of trust in uDCD programs by health professionals and the public.

Expanding the donor pool: donation after cardiac death

Lung transplantation (LTx) is the definitive treatment of patients with end-stage lung disease. Availability of donor lungs remains the primary limitation and leads to substantial wait-list mortality. Efforts to expand the donor pool have included a resurgence of interest in the use of donation after cardiac death (DCD) lungs. Unique in its physiology, lung viability seems more tolerant to the variable durations of ischemia that occur in DCD donors. Initial experience with DCD LTx is promising and, in combination with ex vivo lung perfusion systems, seems a valuable opportunity to expand the lung donor pool.

Ex vivo lung perfusion - state of the art in lung donor pool expansion

Lung transplantation remains the gold standard for patients with end-stage lung disease. Nevertheless, the number of suitable donor lungs for the increasing number of patients on the waiting list necessitates alternative tools to expand the lung donor pool. Modern preservation and lung assessment techniques could contribute to improved function in previously rejected lungs. Ex vivo lung perfusion (EVLP) already demonstrated its value in identification of transplantable grafts from the higher risk donor pool. Moreover, lungs from EVLP did not show significantly different postoperative results compared to standard criteria lungs. This could be explained by the reduction of the ischemia-reperfusion injury through EVLP application. The aim of this article is to review technical characteristics and the growing clinical EVLP experience with special attention to EVLP application for donation after cardiac death (DCD) lungs.

Emergency medical services knowledge and attitudes about non-heart-beating donors: effect of an educational intervention

BACKGROUND

More than 750,000 people die of sudden death each year, and many are potential non-heart-beating donors (NHBDs) for lung transplant. Although critical, the role of emergency medical services (EMS) personnel in assisting with recovery of NHBD lungs has not been studied. The purpose of this study was to assess knowledge of and attitudes about NHBDs among EMS personnel, evaluate the extent to which knowledge and personal experience with organ donation is associated with attitude, and ascertain the effectiveness of an intervention designed to teach EMS professionals about NHBDs.

METHODS

EMS professionals (n = 361) completed measures of knowledge of and attitudes about NHBDs and then watched a presentation by a transplant doctor about traditional organ donation, NHBDs, and transplantation. Participants were able to ask questions during and after the presentation. Participants completed the measures again 3 months later.

RESULTS

EMS professionals had a high rate of personal experience with organ donation and positive attitudes toward traditional organ donation. However, they showed lack of knowledge about NHBDs and felt less skilled in being part of the NHBD process, consistent with knowledge scores. The educational intervention was somewhat effective in improving knowledge about NHBDs. Scores improved significantly on 5 of 13 items.

CONCLUSIONS

Lung recovery from NHBDs offers the potential of a very large supply for transplantation. This research suggests that with additional training, EMS professionals may be willing to be part of a NHBD recovery team.

Lung transplantation from donation after cardiocirculatory death: a systematic review and meta-analysis

BACKGROUND

Lung transplantation (LTx) can extend life expectancy and enhance the quality of life for select patients with end-stage lung disease. In the setting of donor lung shortage and waiting list mortality, the interest in donation after cardiocirculatory death (DCD) is increasing. We performed a systematic review and meta-analysis to compare outcomes between DCD and conventional donation after brain death (DBD).

METHODS

PubMed, CINAHL, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Cochrane Central Register of Controlled Trials, Scopus, Web of Science, and ClinicalTrials.gov were searched. We identified original research studies with 1-year post-transplant survival data involving >5 DCD transplants. We performed meta-analyses examining 1-year survival, primary graft dysfunction, and acute rejection after LTx.

RESULTS

We identified 519 citations; 11 observational cohort studies met our inclusion criteria for systematic review, and 6 met our inclusion criteria for meta-analysis. There were no differences found in 1-year mortality after LTx between DCD and DBD cohorts in individual studies or in the meta-analysis (DCD [n = 271] vs DBD [n = 2,369], relative risk [RR] 0.88, 95% confidence interval [CI] 0.59-1.31, p = 0.52, I(2) = 0%). There was also no difference between DCD and DBD in a pooled analysis of 5 studies reporting on primary graft dysfunction (RR 1.09, 95% CI 0.68-1.73, p = 0.7, I(2) = 0%) and 4 studies reporting on acute rejection (RR 0.72, 95% CI 0.49-1.05, p = 0.09, I(2) = 0%).

CONCLUSIONS

Survival after LTx from DCD is comparable to survival after LTx from DBD in observational cohort studies. DCD appears to be a safe and effective method to expand the donor pool.

Utilization of the Organ Care System Lung for the assessment of lungs from a donor after cardiac death (DCD) before bilateral transplantation

In this manuscript, we present the first experience of evaluating donation after circulatory death (DCD) lungs, using the normothermic preservation Organ Care System (OCS) and subsequent successful transplantation. The OCS could be a useful tool for the evaluation of marginal lungs from DCD donors as it allows a proper recruitment and bronchoscopy in such donations in addition to continuous ex-vivo perfusion and assessment and treatment during transport. The OCS could potentially be a standard of care in the evaluation of marginal lungs from DCD.

Lung donor selection criteria

The criteria that define acceptable physiologic and social parameters for lung donation have remained constant since their empiric determination in the 1980s. These criteria include a donor age between 25-40, a arterial partial pressure of oxygen (PaO2)/FiO2 ratio greater than 350, no smoking history, a clear chest X-ray, clean bronchoscopy, and a minimal ischemic time. Due to the paucity of organ donors, and the increasing number of patients requiring lung transplant, finding a donor that meets all of these criteria is quite rare. As such, many transplants have been performed where the donor does not meet these stringent criteria. Over the last decade, numerous reports have been published examining the effects of individual acceptance criteria on lung transplant survival and graft function. These studies suggest that there is little impact of the historical criteria on either short or long term outcomes. For age, donors should be within 18 to 64 years old. Gender may relay benefit to all female recipients especially in male to female transplants, although results are mixed in these studies. Race matched donor/recipients have improved outcomes and African American donors convey worse prognosis. Smoking donors may decrease recipient survival post transplant, but provide a life saving opportunity for recipients that may otherwise remain on the transplant waiting list. No specific gram stain or bronchoscopic findings are reflected in recipient outcomes. Chest radiographs are a poor indicator of lung donor function and should not adversely affect organ usage aside for concerns over malignancy. Ischemic time greater than six hours has no documented adverse effects on recipient mortality and should not limit donor retrieval distances. Brain dead donors and deceased donors have equivalent prognosis. Initial PaO2/FiO2 ratios less than 300 should not dissuade donor organ usage, although recruitment techniques should be implemented with intent to transplant.

Ex vivo lung perfusion

Lung transplantation (LTx) is an established treatment option for eligible patients with end-stage lung disease. Nevertheless, the imbalance between suitable donor lungs available and the increasing number of patients considered for LTx reflects in considerable waitlist mortality. Among potential alternatives to address this issue, ex vivo lung perfusion (EVLP) has emerged as a modern preservation technique that allows for more accurate lung assessment and also improvement of lung function. Its application in high-risk donor lungs has been successful and resulted in safe expansion of the donor pool. This article will: (I) review the technical details of EVLP; (II) the rationale behind the method; (III) report the worldwide clinical experience with the EVLP, including the Toronto technique and others; (IV) finally, discuss the growing literature on EVLP application for donation after cardiac death (DCD) lungs.

Donation after circulatory death: current practices, ongoing challenges, and potential improvements

Organ donation after circulatory death (DCD) has been endorsed by the World Health Organization and is practiced worldwide. This overview examines current DCD practices, identifies problems and challenges, and suggests clinical strategies for possible improvement. Although there is uniform agreement on DCD donor candidacy (ventilator-dependent individuals with nonrecoverable or irreversible neurologic injury not meeting brain death criteria), there are variations in all aspects of DCD practice. Utilization of DCD organs is limited by hypoxia, hypotension, reduced--then absent--organ perfusion, and ischemia/reperfusion syndrome. Nevertheless, DCD kidneys exhibit comparable function and survival to donors with brain death kidneys, although they have higher rates of primary graft nonfunction, delayed graft function, discard, and retrieval associated injury. Concern over ischemic organ injury underscores the reluctance to recover extrarenal DCD organs since lack of medical therapy to support inadequate allograft function limits their acceptability. Nevertheless, limited results with DCD pancreas, liver, and lung allografts (but not heart) are now approaching that of donors with brain death organs. Pretransplant machine perfusion of DCD kidneys (vs. static storage) may reduce delayed graft function but has no effect on long-term organ function and survival. Normothermic regional perfusion used during DCD abdominal organ retrieval may reduce ischemic organ injury and increase the number of usable organs, although critical confirmative studies have yet to be done. Minor increases in usable DCD kidneys could accrue from increased use of pediatric DCD kidneys and from selective use of DCD/ECD kidneys, whereas a modest increase could result through utilization of donors declared dead beyond 1 hr from withdrawal of life support therapy. A significant increase in transplantable kidneys could be achieved by extension of the concept of living kidney donation in relation to imminent death of potential DCD donors. Progress in research to identify, prevent, and repair DCD-associated organ retrieval injury should improve utilization of DCD organs. Recent results using ex situ pretransplant organ perfusion of DCD organs has been encouraging in this regard.

Should we reconsider lung transplantation through uncontrolled donation after circulatory death?

Lung transplantation through controlled donation after circulatory death (cDCD) has slowly gained universal acceptance with reports of equivalent outcomes to those through donation after brain death. In contrast, uncontrolled DCD (uDCD) lung use is controversial and requires ethical, legal and medical complexities to be addressed in a limited time. Consequently, uDCD lung use has not previously been reported in the United States. Despite these potential barriers, we present a case of a patient with multiple gunshot wounds to the head and the body who was unsuccessfully resuscitated and ultimately became an uDCD donor. A cytomegalovirus positive recipient who had previously consented for CDC high-risk, DCD and participation in the NOVEL trial was transplanted from this uDCD donor, following 3 h of ex vivo lung perfusion. The postoperative course was uneventful, and the recipient was discharged home on day 9. While this case represents a "best-case scenario," it illustrates a method for potential expansion of the lung allograft pool through uDCD after unsuccessful resuscitation in hospitalized patients.

Donation after circulatory death: current status

PURPOSE OF REVIEW

Donor shortage has forced transplant teams to explore new methods to increase the potential donor pool. Donation after circulatory death (DCD) has opened new perspectives and could be a valuable option to expand the brain-dead donors. The purpose of this review is to provide an overview of current practice and to identify remaining questions related to ethical and medical issues that should be further addressed in the future.

RECENT FINDINGS

Recent findings demonstrate acceptable outcomes after DCD kidney and lung transplantation but inferior graft survival for liver transplantation. The impact and importance of the agonal phase following withdrawal of treatment in controlled DCD is increasingly recognized. Premortem interventions are currently under debate related to preservation strategies or comfort therapy. New preservation strategies using in-situ/in-vivo extracorporeal membrane oxygenation or ex-vivo machine perfusion have large potential in the future. Finally, organizations and institutions are reporting more uniform guidelines related to declaration of death and DCD organ procurement.

SUMMARY

DCD donation has regained much attention during the last decade and is now part of standard clinical practice albeit this type of donation should not be regarded as an equally acceptable alternative for donation after brain death. It will be important to further explore the potential of DCD, to monitor the long-term outcomes and to further optimize the quality of these grafts. Development and implementation of uniform guidelines will be necessary to guarantee the clinical use of these donor pools.

Ex vivo lung reconditioning: a new era for lung transplantation

Lung transplantation has come to be viewed as the best treatment option for various end-stage lung diseases. The low number of viable donors continues to be a major obstacle to increasing the number of lung transplants, resulting in high mortality among patients on the waiting list. Unlike transplantation of other solid organs, lung transplantation is primarily limited not by the absolute number of donors but by the viability of the donor lungs, which can be damaged by brain death and by treatments given in the ICU. There are various proposals of ways to increase the number of lung donors: intensification of donation campaigns, use of non-heart-beating donors, living lobar lung transplantation, and adoption of more flexible criteria for donors. However, the proposal that has attracted the most attention from lung transplant groups is ex vivo lung perfusion, especially due to the prospect of reconditioning previously discarded lungs. This system consists of perfusion and ventilation of the isolated heart-lung block using a modified cardiopulmonary bypass circuit. Various authors have been studying this technique due to the satisfactory results obtained and the prospect of an increase in the number of organs suitable for transplantation. Researchers in Sweden, Canada, Austria, England, Spain, and Brazil have extensive experience with the method and have introduced modifications to it. The objective of this article was to review the development of, state of the art in, and future prospects for the ex vivo model of lung perfusion and reconditioning.

The differential tissue expression of inflammatory, oxidative stress, and apoptosis markers in human uncontrolled non-heart-beating donors

BACKGROUND

Uncontrolled non-heart-beating donor (UNHBD) transplantation offers a major opportunity to ameliorate the effects of the donor shortage. However, little is known about the true status of the organs obtained from these donors. UNHBD transplantation is performed under unfavorable conditions and involves exposure to several harmful stimuli that have been identified as triggers for immediate inflammatory response, oxidative stress, and apoptotic phenomena. This adverse scenario could explain the higher rates of graft dysfunction due to primary nonfunction traditionally observed in NHBD. Our aim was to assess the expression of proinflammatory, oxidative, and apoptotic markers in liver, lung, and pancreas tissue samples obtained from UNHBD and to compare these expression levels with those observed in brain-dead donors (BDD).

METHODS

Samples from human type 2 NHBD and BDD were obtained at the end of cold storage. Interleukin (IL)-1β, tumor necrosis factor-α, IL-6, IL-10, endothelial nitric oxide synthase, inducible nitric oxide synthase, type 1 heme oxygenase, type 2 heme oxygenase, Bax, and Bcl-2 protein and mRNA expression, as well as catalase, glutathione peroxidase, and glutathione reductase tissue activity, were determined.

RESULTS

UNHBD showed similar or lower expression of proinflammatory mediators and apoptosis markers in all three organs without modifications to the anti-inflammatory cytokines. Although the major oxidative stress marker levels were also comparable in both types of donors, the type 1 heme oxygenase mRNA expression and antioxidant enzyme activity were slightly diminished in UNHBD.

CONCLUSIONS

The initial tissue damage generated during the UNHB donation process is at least comparable with that observed in BDD. However, although the expression of the immediate immune response and apoptosis markers is similar, a mild impairment of the local antioxidant activity was observed.

Reconditioning lungs donated after cardiac death using short-term hypothermic machine perfusion

BACKGROUND

Hypothermic machine perfusion (HMP) is widely used to preserve kidneys and livers for transplantation. This study investigated whether short-term HMP could improve the quality of lungs donated after cardiac death (DCD).

METHODS

In a clinically relevant uncontrolled DCD model, beagles were divided into two groups (n=5 each): 4 hr warm ischemia + 14 hr static cold storage (SCS group) or 4 hr warm ischemia + 12 hr SCS followed by 2 hr HMP (HMP group). HMP was performed using centrifugal perfusion with STEEN solution at approximately 10°C. In both groups, the left lungs were then transplanted and reperfused for 4 hr to evaluate the posttransplantation lung functions.

RESULTS

HMP was performed safely, not inducing any oxidative damage. The dynamic pulmonary compliance was stable during HMP, whereas the pulmonary vascular resistance significantly decreased. HMP microscopically eliminated residual microthrombi in the donor lungs just before transplantation. The lung tissue adenosine triphosphate levels 4 hr after reperfusion were significantly higher in the HMP group compared with the SCS group. The serum malondialdehyde levels and proinflammatory cytokine levels in the bronchoalveolar lavage fluid 4 hr after reperfusion were significantly lower in the HMP group than in the SCS group. The physiologic lung functions during reperfusion were significantly better in the HMP group compared with the SCS group. HMP also significantly reduced ischemia-reperfusion injury in the microscopic findings.

CONCLUSIONS

Short-term HMP could resuscitate ischemically damaged DCD lungs and ameliorate ischemia-reperfusion injury.

Postmortem and ex vivo carbon monoxide ventilation reduces injury in rat lungs transplanted from non-heart-beating donors

OBJECTIVE

We sought to determine whether ventilation of lungs after death in non-heart-beating donors with carbon monoxide during warm ischemia and ex vivo lung perfusion and after transplant would reduce ischemia-reperfusion injury and improve lung function.

METHODS

One hour after death, Sprague-Dawley rats were ventilated for another hour with 60% oxygen (control group) or 500 ppm carbon monoxide in 60% oxygen (CO-vent group; n=6/group). Then, lungs were flushed with 20 mL cold Perfadex, stored cold for 1 hour, then warmed to 37 °C in an ex vivo lung perfusion circuit perfused with Steen solution. At 37 °C, lungs were ventilated for 15 minutes with alveolar gas with or without 500 ppm carbon monoxide, then perfusion-cooled to 20 °C, flushed with cold Perfadex and stored cold for 2 hours. The left lung was transplanted using a modified cuff technique. Recipients were ventilated with 60% oxygen with or without carbon monoxide. One hour after transplant, we measured blood gases from the left pulmonary vein and aorta, and wet-to-dry ratio of both lungs. The RNA and protein extracted from graft lungs underwent real-time polymerase chain reaction and Western blotting, and measurement of cyclic guanosine monophosphate by enzyme-linked immunosorbent assay.

RESULTS

Carbon monoxide ventilation begun 1 hour after death reduced wet/dry ratio after ex vivo lung perfusion. After transplantation, the carbon monoxide-ventilation group had better oxygenation; higher levels of tissue cyclic guanosine monophosphate, heme oxidase-1 expression, and p38 phosphorylation; reduced c-Jun N-terminal kinase phosphorylation; and reduced expression of interleukin-6 and interleukin-1β messenger RNA.

CONCLUSIONS

Administration of carbon monoxide to the deceased donor and non-heart-beating donor lungs reduces ischemia-reperfusion injury in rat lungs transplanted from non-heart-beating donors. Therapy to the deceased donor via the airway may improve post-transplant lung function.

Normothermic perfusion of donor lungs for preservation and assessment with the Organ Care System Lung before bilateral transplantation: a pilot study of 12 patients

BACKGROUND

Cold flush and static cold storage is the standard preservation technique for donor lungs before transplantations. Several research groups have assessed normothermic perfusion of donor lungs but all devices investigated were non-portable. We report first-in-man experience of the portable Organ Care System (OCS) Lung device for concomitant preservation, assessment, and transport of donor lungs.

METHODS

Between Feb 18, and July 1, 2011, 12 patients were transplanted at two academic lung transplantation centres in Hanover, Germany and Madrid, Spain. Lungs were perfused with low-potassium dextran solution, explanted, immediately connected to the OCS Lung, perfused with Steen's solution supplemented with two red-cell concentrates. We assessed donor and recipient characteristics and monitored extended criteria donor lung scores; primary graft dysfunction scores at 0, 24, 48, and 72 h; time on mechanical ventilation after surgery; length of stays in hospital and the intensive-care unit after surgery; blood gases; and survival of grafts and patients.

FINDINGS

Eight donors were female and four were male (mean age 44·5 years, range 14-72). Seven recipients were female and five were male (mean age 50·0 years, range 31-59). The preharvest donor ratio of partial pressure of oxyen (PaO(2)) to fractional concentration of oxygen in inspired air (F(I)O(2)) was 463·9 (SD 91·4). The final ratio of PaO(2) to F(I)O(2) measured with the OCS Lung was 471·58 (127·9). The difference between these ratios was not significant (p=0·72). All grafts and patients survived to 30 days; all recipients recovered and were discharged from hospital.

INTERPRETATION

Lungs can be safely preserved with the OCS Lung, resulting in complete organ use and successful transplantation in our series of high-risk recipients. In November, 2011, we began recruitment for a prospective, randomised, multicentre trial (INSPIRE) to compare preservation with OCS Lung with standard cold storage.

FUNDING

TransMedics and German Federal Ministry of Education and Research.

Ex vivo rehabilitation of non-heart-beating donor lungs in preclinical porcine model: delayed perfusion results in superior lung function

OBJECTIVES

Ex vivo lung perfusion (EVLP) is a promising modality for the evaluation and treatment of marginal donor lungs. The optimal timing of EVLP initiation and the potential for rehabilitation of donor lungs with extended warm ischemic times is unknown. The present study compared the efficacy of different treatment strategies for uncontrolled non-heart-beating donor lungs.

METHODS

Mature swine underwent hypoxic arrest, followed by 60 minutes of no-touch warm ischemia. The lungs were harvested and flushed with 4°C Perfadex. Three groups (n = 5/group) were stratified according to the preservation method: cold static preservation (CSP; 4 hours of 4°C storage), immediate EVLP (I-EVLP: 4 hours EVLP at 37°C), and delayed EVLP (D-EVLP; 4 hours of CSP followed by 4 hours of EVLP). The EVLP groups were perfused with Steen solution supplemented with heparin, methylprednisolone, cefazolin, and an adenosine 2A receptor agonist. The lungs then underwent allotransplantation and 4 hours of recipient reperfusion before allograft assessment for resultant ischemia-reperfusion injury.

RESULTS

The donor blood oxygenation (partial pressure of oxygen/fraction of inspired oxygen ratio) before death was not different between the groups. The oxygenation after transplantation was significantly greater in the D-EVLP group than in the I-EVLP or CSP groups. The mean airway pressure, pulmonary artery pressure, and expression of interleukin-8, interleukin-1β, and tumor necrosis factor-α were all significantly reduced in the D-EVLP group. Post-transplant oxygenation exceeded the acceptable clinical levels only in the D-EVLP group.

CONCLUSIONS

Uncontrolled non-heart-beating donor lungs with extended warm ischemia can be reconditioned for successful transplantation. The combination of CSP and EVLP in the D-EVLP group was necessary to obtain optimal post-transplant function. This finding, if confirmed clinically, will allow expanded use of nonheart-beating donor lungs.